Fuel burner construction



Patented May 18, 1943 FUEL BURNER CONSTRUCTION Sylvanus C. Shipley, Benjamin Cyr, and Frederick S. Denison, Minneapolis,

Minn., assignors to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application October 30, 1939, Serial No. 301,888

2 Claims. (01. 1585116) The present invention relates to fluid fuel burners and its object is to provide structural improvements to increase their efficiency and reliability as wellas to provide improved, more convenient and economical methods of manul'acture.

While our invention is not limited to pilot burners,".being applicable to fuel burners of all types it is particularly adaptable to pilot, burners of the type used with safety means including a temperature responsive device having a small flame impinging thereon spaced from a larger igniting flame, the function of the pilot burner flames being to ignite a main burner flame and to energize the temperature responsive device. In

arrangements of this general character it has heretofore been proposed to provide a pilot burner in the form of a tube having spaced openings for the two pilot flames and a series of smaller openings to provide a runner flame between the two larger flames. The heretofore proposed arrangements have also contemplated admitting the gas to the pilot'burner at such a point intermediate the two said flames that upon a drop in gas pressure the pressure would drop sooner at the flame energizing the temperature responsive device so that the latter device would perform its safety function of shutting down the system before the igniter flame would recede sufficiently to be unable to perform its function. Our contribution to the art resides principally in an improved structural arrangement; for producing a runner or ladder flame between the igniter flame and the smaller flame impinging on the temperature responsive deviceof pilot burners of'the general type which, as pointed out above, are known to the art or have heretofore been proposed. We do notintend to propose any claims herein directed to the heretofore known and proposed arrangements but only to our particular improvements to which the appended claims are directed.

A more particular object is to form a pilot burner having a runner flame by rolling a strip of metal having a serrated edge until the said edge abuts a relatively smooth edge to form a tubular structure having closely spaced relatively small openings between the serrations. The ultimate aimof this object is to avoid the diiflculty of drilling closely small spaced holes in the tube to provide a runner flame and to insure proper propagation of the runner flame. The openings between the serrations as described may of course beclosely spaced between the extremities of serrations or teeth thus assuring that the flame, can spread from one opening to the next.

Another particular object of our invention is to provide openings in a gasconveying means by arranging a smoothedge of material in abutting relation with a; serrated edge soas to leavesmall closely spacedopenings between the serrations through which gas may pass to supply a runner flame along the abutting edges.

Another object is to provide a pilot burnerin the form of a tubular member having spaced openings and a second tube longitudinally. posi-' tioned within the tubularmember and terminating at a point therewithin for admitting gas thereto. This arrangementofiers the-advantage of neatness and compactness of the unit.

For a better understanding of our invention reference may be made to the following detailed description and annexed drawing disclosing a preferred embodiment of the invention when adapted to pilot burners, it being understood of course as pointed out above that the principles of our invention may be advantageously adapted to other types of burners as well.

Figure 1 is a diagrammatic view of an industrial gas burning system utilizing-the pilot burner of our invention. V

Figure 2 is a detail cross-sectional view of the pilot burner mounted within a suitable housing or casings t I v Figure 3 is a View of the burner tube at one stage in the process of its construction.

Figure 4 is another view of the burner tube at an earlier stage in the process of its construction,and a Figure 5 is a view of another form of our invention wherein the burner tube is bent at an angle rather than being straight. The burner tube of Figure 2 could of course be shaped as shown in Figure 5. r

Referring to the drawing, Figure 1 shows in diagrammatic form an industrial gas burning system showing the furnace wall at 40, a main burner at H, and. the pilot burner assembly of our invention designated generally at l2.

Figure 2 shows the details of the pilot burner in cross section, numeral 13 designating a fitting in the form of a casting having a body portion and a more or less cylindrical portion I4 extending to the left therefrom. The fitting I3 has an internal bore l5 extending longitudinally of the portion I4 and having a screw threaded counter- I bore [6 at its left end. The bore l5v is also screwthreaded and engagingin screw-threaded relation therewith is an orifice plug I! having a longitudinal orifice I8 therein through which gas is metered to the pilot burner. Adjacent the inner;

end of the orifice plug I! are openings I9 and in the portion I4 of the fitting, the purpose of which is to admit air into the bore I5 to mix with the gas being admitted through the orifice plug H in order to form a combustible mixture, it being understood that this pilot burner is a Bunsen burner.

The right end of the bore I5 has a counterbore 22 and fitted in this counter-bore is the left end of a burner tube 23. The burner tube 23 has its right end closed by a suitable cap 24 and adjacent this end is an opening 25 through which gas passes for supplying a pilot flame 26. Adjacent the opposite end of the tube 23 is a smaller opening 21 through which gas passes for supplying a smaller flame 29. Arranged in a line in uniform spaced relation between the openings 25 and 21 is a plurality of closely spaced small openings 28 through which gas is adapted to pass for supplying a continuous runner or ladder flame between the openings 21 and 25. The particular manner in which we construct the pilot burner tube 23 forms an important part of our invention which will presently be described.

The upper part of the fitting I3 has a bore or opening 30 communicating with a larger screwthreaded counter-bore 3|, the lower part of which is of conical shape. Numeral 32 designates a clamping nut having an opening 33 extending therethrough which is in screw-threaded relationship with the counter-bore 3I and interposed between the clamping nut 32 and the bottom of the counter-bore 3| is compression ferrule material 34, there being a thermocouple extending through the clamping nut 32, through the ferrule 34 and the bore 30. Obviously the construction of the upper part of the fitting I3 forms a clamping means constituting a suitable mounting for the thermocouple element 35. The tip of the thermocouple element 35 assumes a position in which the flame 29 impinges thereon for purposes of energizing the thermocouple. Obviously the position of the thermocouple can be adjusted with respect to the flame 29.

Figures 3 and 4 illustrate steps in the process of manufacture of the burner tube 23. In Figure 4 numeral 38 represents a strip of material of suitable gauge having a notch or depression 25 in theedge adjacent the right end of the strip.

The notch 25 appears as the opening 25 in Fig- 1 ure 2. Adjacent the opposite edge 4| of the strip near the left end is the smaller opening 21 previously described in connection with Figure 2. The openings designated by the numeral 28 in Figure 2 appear as a plurality of uniformly spaced .2

notches 28 in Figure 4 extending along the edge 40 of the strip 38. The strip 38 is preferably of stamped construction and after it has been stamped into the form and shape shown in Figure 4 the strip is then rolled into a tube as seen in Figure 3 with'the edges 40 and Ill being brought into or practically into abutting relation. Thus obviously the notch or depression 25 forms an opening in the resultant tube 23 on the same side of the tube as the smaller opening 27. notches 28 form a plurality of uniformly spaced openings extending in a line substantially between the openings 25 and 21. It will be understood that various types of notches may be made in the edge of the strip 38 or this edge may be otherwise serrated such as by knurling so that when this edge is brought into abutting relation with the opposite edge of the strip a series of closely spaced openings will be formed in the resultant tube.

The .7

The tube 23 having been formed as seen in Figure 3, its left end is fitted into the counterbore 22 of the fitting I3 in the manner seen in Figure 2. Numeral 43 designates a smaller tube, the left end of which is fitted into the bore I5 and the right end of which extends to a point within the tube 23 intermediate the openings 25 and 21. The right end of tube 43 is closer to the opening 25 than the opening 27. The purpose of this arrangement is so that in the event of a drop in pressure being supplied to the pilot burner the pressure will drop sooner adjacent the flame 25 than adjacent the flame 26 and consequently the thermocouple 25 will be deenergized before the flame 26 has receded appreciably.

Numeral 44 designates a generally longitudinal housing within which the pilot burner unit is mounted, the casing 44 having an opening 45 near its right end through which the flame 26 is adapted to project. At the left end of the housing 44 is a hinged shutter 45 having a screw 47 for purposes of adjusting the amount of opening of the shutter so as to vary the amount of air being admitted to the left end of the housing 44. The air which is admitted to the left end of the housing 44 is free to pass around the sides of the upper part of the fitting I3 so as to supply air for combustion at the flames 26, 29 and the runner flame.

Referring again to Figure 1, numeral 48 designates a gas supplying pipe to which gas is supplied to the main burner II. Interposed in this pipe adjacent the main burner I I is an electrically actuated vaive 49 which is controlled by a space thermostat 59 of suitable construction. The thermostat 50 comprises a bimetal element 5| arranged to actuate a movable switch blade 52 cooperable with a fixed electrical contact 53. The thermostat 55 controls an electrical circuit for the valve 49 formed by the wires 54, 55 and 56. Interposed in the gas supply conduit 48 ahead of the valve 46 is a second electromagnetically controlled valve '56 which is normally energized by the thermocouple element .35,

through wires contained in a conduit 51 extending between the valve 56 and the thermocouple 35 within the unit I2. Numeral 58' designates a suitable fitting in the conduit 48 between the valves 56 and 49 from which gas isnormally continually bled off through a tube 59 which connects to the screw-threaded counter-bore I6 in the portion I4 of fitting I3 so as to supply fuel for the pilot burner flames.

It will be understood that in operation whenever the thermostat 53 closes its circuit through the blade 52 and contact 53 the valve 49 isopened admitting gas to the main burner where it is ignited by the pilot flame 26. Th pilot flame 26 normally burns continuously and in the event of extinguishment of the pilot flame by reason of gas pressure failure or otherwise the thermocouple element 35 will be deenergized causing closure of the electromagnetic valve 56 which is normally open. In the event of such an occurrence gas is of course cut off from the main burner I! and the supply cannot be reinitiated until the pilot bin'ner has been manually relit.

From the foregoing it will be appreciated by those skilled in the art that we have provided a pilot burner wherein in the event of failure of the pilot flame the supply of .gas to the main burner is immediately terminated. The construction is advantageous in that as seen in Figure 1 the left end of the unit I2 extends .exteriorly of the combustion chamber so that the thermocouple element 35 is readily accessible and is kept away from the heat of the main burner l I. The manner of construction of the pilot burner tube 23 is of particular importance inasmuch as it lends itself ideally to ease and economyof manufacture particularly by reason of the stamped construction. By forming the pilot burner tube by rolling a stamped strip in the manner described the small spaced openings providing for the runner flame are formed with a maximum of ease and facility and may readily be spaced to insure proper propagation of flame. This particular manner of forming the tube avoids the rather pronounced difficulty of attempting to provide a plurality of uniformly spaced openings for a runner flame by drilling the openings in a preformed tube.

Referring to Figure 5, in some instances it is desirable that the right end of the pilo ifibutner tube 23 be brought nearer to the opening 45 in the housing 44. Thus as seen in Figure 5 the right end of the tube 23 may be bent upwardly at an angle as shown.

In the appended claims it is to be understood that the term "serrations defines any form that the edge of the strip 38 may have whereby openings as described are produced when the strip is rolled into a tube.

The embodiments of our invention which we have disclosed are representative of preferred forms of its construction and of the process of making it. Variations may be made in the form of the finished product by those skilled in the art and there are variations which may be utilized by those skilled in the art in the process of making the pilot burner without departing from the spirit and scope of the invention. It is to be understood that our disclosure herein is illustrative in that we are to be limited only in accordance with the scope of the appended claims.

We claim as our invention:

1. A gaseous fuel burner comprising a single sheet-like member, said member having a first edge and a second edge opposite said first edge, at least one of said edges being serrated over a substantial portion of its length, said member being in the form of a hollow conduit 50 that said two edges are directly opposite each other and in abutting relationship throughout the length of the serrated portion whereby said serrations form openings for the gaseous fuel.

2. A gaseous fuel burner comprising a single sheet-like member, said member having a first edge and a second edge opposite said first edge, at least one of said edges having a series of relatively small serrations and a relatively large serration at the end of the series, said serrations extending throughout a substantial portion of the length of said edge, said member being in the form of a hollow conduit so that said two edges are directly opposite each other and in abutting relationship throughout the length of the serrated portion whereby said relatively small serrations provide a runner flame to said relatively large serration.

SYLVANUS C. SHIPLEY. l BENJAMIN CYR.

FREDERICK S. DENISON. 

